The present invention is directed to an expansion dowel assembly including an anchor bolt having an expanding member located at the leading end of a cylindrical shank with the shank having means adjacent the opposite end for connecting a load to the dowel assembly. An expansion sleeve laterally encloses the anchor bolt and is axially displaceable relative to it. Slots are formed in the expansion sleeve extending from its leading end toward the trailing end. The inside diameter of the expansion sleeve corresponds to the outside diameter of the shank, and the sleeve has a circumferentially extending cutting tooth at its leading end.
Expansion dowel assemblies of the above type, as disclosed in British Pat. No. 2 109 886 B, are anchored by driving the expansion sleeve over the expanding member on the anchor bolt with the expanding member supported at the base of a borehole. The expansion sleeve expands radially as it moves relative to the expanding member. The cutting tooth located at the front end of the expansion sleeve provides an undercut in the surface of the borehole. When a pulling force is applied to the anchor bolt, an after-expansion of the expansion sleeve is effected. Due to the relatively flat cone angle of the expanding member on the anchor bolt, very high expansion forces are developed in the expansion dowel assembly. Such expansion forces can exert an explosive effect on the receiving material in which the borehole is formed. Therefore, the known expansion dowel assembly is suitable for use in a cracked receiving material only under certain conditions. Furthermore, the energy required to drive the expansion sleeve is relatively high, because of the single cutting tooth.